Inverted selector mechanism

ABSTRACT

A selector mechanism including a line relay, a selector magnet, circuitry controlled by the line relay for energizing the selector magnet whenever the line relay is deenergized and vice versa, and means controlled by the selector magnet for producing a marking output whenever the selector magnet is deenergized and for producing a spacing output whenever the selector magnet is energized.

United States Patent Inventor Arthur A. Hagstrom Hoffman Estates, lll.

Appl. No. 770,159

Filed Oct. 24, 1968 Patented May 25, 1971 Assignee Teletype CorporationSkokle, lll.

INVERTED SELECTR MECHANIS 2 Claims, 4 Drawing Figs.

US. Cl 178/33 Int. Cl. 11041 17/16 Field of Search 178/33 [5 6]References Cited UNITED STATES PATENTS 2,595,745 5/1952 Zenner 178/33Primary Examinerl(athleen l-l. Clafiy Assistant Examiner-Thomas W. BrownAttorneys.l. L. Landis and R. P. Miller ABSTRACT: A selector mechanismincluding a line relay, a selector magnet, circuitry controlled by theline relay for energizing the selector magnet whenever the line relay isdeenergized and vice versa, and means controlled by the selector magnetfor producing a marking output whenever the selector magnet isdeenergized and for producing a spacing output whenever the selectormagnet is energized.

PATENTED W25 ism 3581; 004

PRIOR ART 7 Z;D 1 FIG.

= INVENTOR ARTHUR A. HAGSTROM MZwMcwHLV ATTORNFY INVERTED SELECTORMECHANISM BACKGROUND OF THE INVENTION Telegraph receivers and othersignal-responsive devices almost universally employ a selector magnetand an armature operated thereby for converting incoming electricalsignals into mechanical movements. In the early days of telegraphyselector magnets were connected directly to telegraph lines, however, itsoon .became the practice to connect a highly responsive line relay tothe line and to use the line relay to control a selector magnetenergizing circuit. Traditionally telegraph signals include a no currentstart bit and a current stop bit and, accordingly, line relaysresponding to such signals remain energized during idle periods. In thepast the selector-magnet-driving circuits controlled by line relays havebeen arranged to energize their respective selector magnets whenevertheir respective line relays are energized, that is, to operate theselector magnets as if they were connected directly to the incomingline. This practice causes the selector magnets of low usage telegraphreceivers to. remain energized for long periods of time thereby creatingan unnecessary power drain in the selector-magnet-driving circuits ofsuch devices and also causing the armatures of such selector magnets totend to stick" due to accumulations of oil and residual magnetism, bothof which conditions. are aggravated by long periods of selector magnetenergization. Simply reversing the selector-magnet-driving circuits oflow usage telegraph receivers so that the selector magnet is deenergizedwhenever the line relay is energized without also reversing the outputof the selector magnet is an inadequate solution'since itwould requirethe complete redesign of all such low usage receivers.

SUMMARY OF THE INVENTION In the preferred embodiment a selectormechanism in which the selector magnet is deenergized during idleperiods is comprised of means for receiving signals including start bitsand stop bits, aselector magnet, circuitry responsive to the receivingmeans for energizing the selector magnet whenever a start bit isreceived and for deenergizing the selector magnet whenever a stop bit isreceived and means responsive to the selector magnet for providing anoutput indicative of the receipt of a start bit whenever the selectormagnet is energized and for providing an output indicative of thereceipt of a stop bit whenever the selector magnet is deenergized.

DESCRIPTION OF THE DRAWING A more complete understanding of theinvention may be had by referring to the following detailed descriptionwhen taken in conjunction with the drawing wherein:

FIG. 1 a schematic illustration of a conventional selector mechanism;

FIG. 2 is a schematic illustration of one embodiment of the presentinvention;

FIG. 3 is a partial top view of the selector mechanism shown in FIGS. 1and 21; and

FIG. 4 is a schematic illustration of another embodiment of the presentinvention.

DETAILED DESCRIPTION Referring now to the drawing, wherein likereference numerals designate like parts throughout the several views,and referring particularly to FIG. I, there is shown a telegraph line 11extending from a remote transmitter (not shown), such as a tape reader,a keyboard, or the like, to a line relay 12. The telegraph line 11conveys signals comprised of current (marking) bits and no current(spacing) bits which serve to energize and deenergize the line relay I2,respectively. The line relay 12 operates an armature 13 which isnormally positioned in the dash line position in FIG. 1 and which isdriven to the full line position whenever the line relay 12 isenergized. The armature 13 operates to connect a source of electricalpotential 14 to a selector magnet 15. Accordingly, the selector magnet15 is energized by the source of potential 14 whenever the line relay 12is energized by a marking bit on the line 11.

The selector magnet 15 operates to control the positioning of a selectormagnet armature 16 which is normally driven to the dash line positionshown in FIG. I by a spring 17 and which is driven to the full lineposition shown in FIG. 1 against the action of the spring 17 wheneverthe selector magnet 15 is energized. The selector magnet armature 16controls the positioning of a start lever 18, a spacing lock lever 19and a marking lock lever 20 which together form the output of theselector mechanism.

In use, the telegraph line 11 is maintained in a current or markingcondition during all idle or rest periods. Accordingly, during suchperiods, the line relay 12 is maintained in an energized condition, theline relay armature I3 is held in the full line position shown in FIG.1, the source of potential 14 is connected through the armature 13 tothe selector magnet 15 and the selector magnet armature 16 is held inthe full line position shown in FIG. 1 due to the energization of theselector magnet 15. During rest periods the start lever 18 is drivenagainst the end of the selector magnet armature 16 by a spring (notshown) and the spacing lock lever 19 and the marking lock lever 20 areheld out of engagement with thearmature 16 by a cam (not shown).

Telegraph signals traditionally begin with a spacing pulse and,accordingly, whenever a signal is received by the selector mechanism ano current bit is delivered through the telegraph line 11 to the linerelay 12. The spacing bit deenergizes the line relay 12 thereby allowingthe line relay armature 13 to return to the dash line position shown inFIG. 1. This disconnects the source of potential 14 from the selectormagnet 15 which in turn allows the selector magnet armature 16 to movefrom the full line position shown in FIG. 1 to the dash line positionshown therein under the action of the spring 17. When the selectormagnet armature 16 moves tothe dash line position the start lever 18immediately moves toward the selector magnet armature 16 which actionindicates the rotation of a selector cam shaft (not shown). As theselector cam shaft begins its rotation the start lever 18 is cammed awayfrom the selector magnet armature 16 and the spacing lock lever 19 andthe marking lock lever 20 are permitted to move toward the selectormagnet armature 16 under the action of springs individual to them (notshown).

Telegraph signals include a plurality of intelligence bits, which may beeither marking or spacing bits, that are transmitted over the telegraphline 11 to the line relay 12 immediately after the spacing start bit.The selector cam shaft includes a flutter cam which permits the spacinglock lever 19 and the marking lock lever 20 to move toward the selectormagnet armature 16 during the receipt of each intelligence bit and whichcams the levers 19 and 20 away from the armature 16 at the end of eachintelligence bit. If a particular bit is marking, the line relay 12 isenergized, the source of potential 14 is connected to the selectormagnet 15, and the selector magnet armature 16 is moved to the full lineposition shown in FIG. 1. As the spacing lock lever 19 and the markinglock lever 20 move toward the selector magnet armature 16 the spacinglock lever 19 is'blocked while the marking lock lever 20 is permitted tomove freely toward the armature 16 under the action of its spring-If aparticular bit is spacing, on the other hand, the line relay 12 isdeenergized, the source of potential 14 is disconnected from theselector magnet 15 and the selector magnet armature 16 is driven to thedash line position shown in FIG. 1 by the spring 17. Accordingly, as thespacing lock lever 19 and the marking lock lever 20 are permitted tomove toward the selector magnet armature 16 the marking lock lever 20 isblocked while the spacing lock lever 19 is permitted to move freelyunder the action of its spring. Various levers (not shown) arecontrolled by the operation of the spacing lock lever 19 and the markinglock lever 20 and serve to operate a telegraph mechanism in accordancewith the received signal.

Traditionally telegraph signals invariably end with a marking stop bitwhich operates to energize the line relay 12, thereby connecting thesource of potential 14 to the selector magnet which in turn moves theselector magnet armature 16 to the full line position shown in FIG. 1.During the receipt of the stop bit the selector cam finishes its cycleof rotation and during the terminal portion of its rotation operates tocam the spacing lock lever 19 and the marking lock lever away from theselector magnet armature 16 and to permit the start lever 18 toengagethe end of the selector magnet armature 16. This action returnsthe selector mechanism to its rest condition.

The mechanism shown in FIG. 1 operates very well and would be perfectlysatisfactory were it not for the fact that the mechanism shown in FIG. 1maintains the selector magnet 15 in an energized condition during restperiods. This causes a power drain which can be excessive in low usageof teletypewriters. The selector mechanisms shown in FIGS. 2 and 4operate to overcome this disadvantage while providing exactly the sameoutput as the mechanism shown in FIG. 1 so that the parts of theteletypewriter controlled by the selector mechanism are not affected inany way whatsoever.

Referring now to FIG. 2 and comparing the selector mechanism showntherein with the selector mechanism shown in FIG. 1, it will be seenthat the two mechanisms are identical except for two very importantdetails. First, the selector magnet 15 of the selector mechanism shownin FIG. 2 is positioned to drive the selector magnet armature 16 to itsdash line posi tion while the spring 17 is positioned to drive thearmature 16 to its full line position. Second, the line relay armature13 is arranged to connect the source of potential 14 to the selectormagnet 15 whenever the line relay 12 is deenergized and to disconnectthe selector magnet 15 from the source of potential l4 whenever the linerelay 12 is energized. Thus, during the rest condition the selectormagnet 15 is deenergized but the armature 16 is maintained in its fullline position by the spring 17, that is, the armature 16 is maintainedby the spring 17 in the same position in which the armature 16 of thedevice shown in FIG. I is maintained by the selector magnet 15.

Whenever a spacing bit is received by the device shown in FIG. 2 therelay 12 is deenergized and the armature 13 connects the source ofpotential 14 to the selector magnet 15 which in turn drives the selectorarmature 16 to its dashed line position against the action of the spring17. Whenever a marking bit is received the relay 12 disconnects thesource of potential 14 from the magnet IS-and the spring 17 drives thearmature 16 to its full line position. The start lever 18, the spacinglock lever 19 and the marking lock lever 20 operate with respect to theselector magnet armature 16 in a manner identical to their manner ofoperation with respect to the armature 16 of'the device shown in FIG. 1and, accordingly, the selector mechanism shown in FIG. 2 operates toprovide an output identical to the output provided by the selectormechanism shown in FIG. 1 without the necessity of a power drain throughthe selector magnet 15 during rest periods.

Referring now to FIG. 4 there is shown a selector mechanism thatprovides the results provided by the mechanism shown in FIG. 2 in asomewhat different manner. The line relay armature 13 is again arrangedto connect the source of potential 14 to the selector mechanism 15whenever the line relay 12 is deenergized and to disconnect the sourceof potential 14 from the selector magnet 15 whenever the line relay 12is energized. The selector magnet 15, however, is arranged in the mannershown in FIG. 1, that is, the selector magnet 15 is positioned to raisethe selector magnet armature 16 to the dash line position shown in FIG.4 whenever it is energized while the spring 17 is arranged to drive theselector magnet armature 16 to the full line position whenever theselector magnet 15 is deenergized. Thus the selector magnet 15, theselector magnet armature l6 and the spring 17 are arranged in a manneridentical to their arrangement in FIG. 1.

In order to provide an output identical to the output of the selectormechanism shown in FIG. 1 without the requirement of the energization ofthe selector magnet 15 during idle periods the levers 18, 19 and 20shown in FIG. 4 are arranged to respond to opposite positioning of theselector magnet armature 16. Thus, the start lever 18 is arranged tomove under the armature 16 whenever the armature 16 moves to its dashline position under the action of the selector magnet 15 rather than tomove over the armature l6 whenever the selector magnet armature 16 movesto its full line position under the action of the spring 17 as is thecase in the selector mechanism shown in FIG. 1. Similarly, thearmature-engaging portion of the spacing lock lever 19 of the selectormechanism shown in FIG. 4 is arranged identically to thearmature-engaging portion of the marking lock lever 20 of the selectormechanism shown in FIG. 1 so that the spacing lock lever 19 of theselector mechanism shown in FIG. 4 is blocked from leftward movementwhenever the armature 16 is in its full line position. Likewise, thearmature-engaging portion of the marking lock lever 20 of the selectormechanism shown in FIG. 4 is arranged identically to thearmature-engaging portion of the spacing lock lever 19 of the selectormechanism shown in FIG. 1 so that the marking lock lever 20 of theselector mechanism shown in FIG. 4 is blocked from leftward movementwhenever the armature 16 is in its dash line position. Because thearmature 13 connects the source of potential 14 to the selector magnet15 whenever the relay 12 is deenergized and disconnects the source 14from the magnet 15 whenever the relay 12 is energized the selectormagnet armature 16 of the selector magnet shown in FIG. 4 is positionedin its dash line position during spacing bits and is positioned in itsfull line position during marking bits. Therefore, since they arearranged to respond to opposite armature positions from those theyrespond to in the device shown in FIG. 1 the levers 18, 19 and 20operate to provide an output identical to the output of the levers 18,19 and 20 of the selector mechanism shown in FIG. 1 even though theselector magnet 15 of the selector mechanism shown in FIG. 4 isdeenergized during idle periods.

Although only two embodiments of the invention are illustrated in thedrawing andare described in the foregoing specification it will beunderstood that various other embodiments can be designed and thatvarious modifications of the embodiments shown can be provided withoutdeparting from the spirit of the invention.

1 claim:

1. In a telegraph selector-magnet-energizing circuit for controlling themovement of a selector magnet armature from a first position engaging aspacing lock lever of a selector mechanism to a second position engaginga marking lock lever of the selector mechanism in response to ano-current signal condition impressed on a normally energizedtransmission v line:

resilient means for urging the selector magnet armature into the firstposition to engage the spacing lock lever;

a selector magnet for moving the selector magnet armature from the firstposition to the second position;

a circuit means including a contact movable from an open position to aclosed position for energizing said selector magnet to move the selectormagnet armature into engagement with the marking lock lever; and

a line relay connected to the transmission line and normally energizedfor holding said contact in the open position to maintain said selectormagnet deenergized and said selector magnet armature in'the firstposition, and said line relay responsive to a no-current signalcondition on the transmission line for releasing said contact to moveand complete said circuit means to energize the selector magnet to movethe selector magnet armature into engagement with the marking locklever.

2. A telegraph signal selector mechanism including a start lever, aspacing lock lever, a marking lock lever, a selector magnet armaturemounted to pivot from a position engaging the start lever and thespacing lock lever to a position engaging the marking lock lever, arelay armature mounted to pivot from a first to a second position, and aline relay connected to circuit means responsive to the movement of therelay armature for applying a current to said selector magnet means whenthe relay armature is in the second position and for interrupting thecurrent to said selector magnet means upon movement of the relayarmature to the first position.

1. In a telegraph selector-magnet-energizing circuit for controlling the movement of a selector magnet armature from a first position engaging a spacing lock lever of a selector mechanism to a second position engaging a marking lock lever of the selector mechanism in response to a no-current signal condition impressed on a normally energized transmission line: resilient means for urging the selector magnet armature into the first position to engage the spacing lock lever; a selector magnet for moving the selector magnet armature from the first position to the second position; a circuit means including a contact movable from an open position to a closed position for energizing said selector magnet to move the selector magnet armature into engagement with the marking lock lever; and a line relay connected to the transmission line and normally energized for holding said contact in the open position to maintain said selector magnet deenergized and said selector magnet armature in the first position, and said line relay responsive to a no-current signal condition on the transmission line for releasing said contact to move and complete said circuit means to energize the selector magnet to move the selector magnet armature into engagement with the marking lock lever.
 2. A telegraph signal selector mechanism including a start lever, a spacing lock lever, a marking lock lever, a selector magnet armature mounted to pivot from a position engaging the start lever and the spacing lock lever to a position engaging the marking lock lever, a relay armature mounted to pivot from a first to a second position, and a line relay connected to a transmission line for moving the relay armature into the first position in response to a current flow in the transmission line, wherein the improvement comprises: resilient means connected to the selector magnet armature for urging the selector magnet armature to engage the start lever and the spacing lock lever; a selector magnet means for moving the magnet armature to engage the marking lock lever; and circuit means responsive to the movement of the relay armature for applying a current to said selector magnet means when the relay armature is in the second position and for interrupting the current to said selector magnet means upon movement of the relay armature to the first position. 